Here is the full list of all 19 Action Alien achievements.
Earn a total of 10 000 credits.
Kill 10 000 aliens.
Blow up 500 aliens with grenades.
Unlock all golden weapons.
Unlock all upgraded weapons.
Kill an alien boss with the pistol.
Unlock all perks.
Complete the petrol station map.
Kill 15 boss aliens.
Demolish a part of a building with the grenade launcher.
Use every weapon during one game.
Complete the tropical hotel map.
Beat 100 aliens with leg kicks.
Complete the wasteland map.
Kill 1 000 aliens.
Empty all the rounds of a revolver with only deadly shots in less than 5 seconds.
Blow up 8 aliens with one grenade.
Kill an alien with the last bullet of a machine gun or an assault rifle.
Kill 100 aliens.